It's tempting to haul out clichés about seeing double when talking about New Trier High School's sophomore class, which, with 44 sets of twins and one set of triplets, was certified as a world record by the Guinness World Records organization.

But the dozens of students who gathered Wednesday at New Trier's Winnetka campus to celebrate the record were anything but carbon copies of each other.

Some were not only opposite genders but different heights and, in two cases, even had different birth dates. Others, like Northfield sisters Molly and Shelby Jacob, were near perfect mirror images, but had different interests and personalities.

All were part of a successful effort by Wilmette twins Ryan and Luke Novosel, who, with support from the school district, gathered the documentation needed to win a spot in the Guinness Book of World Records for the most number of twins in the same academic year at one school.

Their numbers are noteworthy, given that the class has slightly more than 1,000 students, according to New Trier officials. The Centers for Disease Control and Prevention put the rate of U.S. twins at 33.5 per 1,000 births in 2015, making New Trier's sophomore class statistically impressive.

Even more so is the fact that some sophomore twins chose not to take part in the project, and that other New Trier classes also boast twins, Winnetka campus principal Denise Dubravec said Wednesday.

According to New Trier, of the participating sophomore twins, one set lives in Glenview. Three more sets live in Northfield, seven sets call Glencoe home, and 11 sets of twins hail from Winnetka.

Most, 22 sets of twins, and the triplets, come from Wilmette. Many were part of Ryan and Luke's first record-setting effort: They got their fifth grade class at Wilmette's Highcrest Middle School certified for the same record back in 2013, with 24 sets.

Nancy Fendley, Ryan and Luke's mother, said her sons always had New Trier in mind for future record setting, because they knew there would be a larger class in which to find twins.

"We knew we had another record waiting, coming into New Trier," Luke said.

As freshmen in 2016, Ryan and Luke started once again gathering the paperwork by the Guinness World Records organization from partipating twins. Among the facts they learned, Fendley said: 70 percent of the participating multiples were born in Chicago or Evanston; 19 sets were girls, 11 were boys, and 14 were mixed-gender. Two families had two sets of twins, she said.

Guinness officials certified the numbers last May, although they didn't send word to Ryan and Luke until January, Fendley said. When they did, Ryan and Luke learned their class set two records, one for the most number of twins, and one for the highest numbers of multiples, thanks to the triplets.

Luke, who his mother identified as the calm twin in the partnership, was level-headed about the record.

"It's not a skill record, or an academic record," he said, though he described it as "fun."

Fraternal twins like Ryan and Luke are born after two eggs are fertilized at the same time. They comprise the majority of twins, according to the CDC, and can be opposite sex siblings who may not even look alike. Identical twins, born when a single fertilized egg splits and develops into two same-gender siblings, occur in only about 3.5 per 1,000 births, according to the CDC.

New Trier's sophomore group has four sets of identical twins, including Molly and Shelby. Shelby, who likes photography, said she and Molly, a horseback rider, "like doing our own things." But she also said the two like knowing they have each other's backs.

Identical or fraternal, New Trier's twins have close ties. Katherine and Tommy Figura both study engineering. They were born minutes apart, but on different days, Katherine said. Katherine likes English while Tommy likes Latin, and Tommy towers several inches above his sister.

Katherine and Tommy said having a twin gives them an ally for life.

"He doesn't get sick often, but when he does, and I have to go to school alone, it feels empty beside me," Katherine said.